If you asked me what Barack Obama is, I could probably give the following replies:
He is a man. He is a human. He is a president. He is a father. Etc.
Obama is all of those, and yet none of them are really unique are they? There are many who are human, many who are men, many fathers, even many presidents.
In a recent discussion it was said that one theory of language is not that we learn how to define words, but that we learn how to use them. I think the same applies here. It is not that we learn how to define persons, but that we learn to recognize them.
Is there a similar list of roles/traits that God has that describes what he is?
Exodus 3:14 - And God said to Moses, "I AM WHO I AM."
Deuteronomy 4:31 - For the LORD your God is a merciful God.
Nehemiah 9:33 - Yet you have been righteous in all that has come upon us, for you have dealt faithfully and we have acted wickedly.
Psalm 25:8 - Good and upright is the Lord.
Psalm 147:5 - Great is our Lord, and abundant in power; his understanding is beyond measure.
Isaiah 6:3 - Holy, holy, holy is the Lord of hosts.
Jeremiah 23:23 - Am I a God at hand, declares the LORD, and not a God far away?
Malachi 3:6 - For I am the Lord, I do not change.
Matthew 19:26 - With God all things are possible.
1 John 4:8 - God is love.
How's that for a start?